Burgers sold at fast-food chains and grocery stores across the US might not be what you think they are

A new report reveals that more than one in ten burger brands across the US contains pathogens, unexpected ingredients, and other contaminants — including rat DNA.

Food analytics platform Clear Labs identified problems with ingredient substitutions, hygiene, and contamination in 13.6% of the 258 burger products the company analysed on a molecular level, in a report released on Tuesday. The company analysed ground meat, frozen patties, fast-food burger products, and veggie burger products.

Some of the most jarring numbers: 4.3% of samples contained traces of pathogenic DNA, rat DNA was found in three products, and human DNA was discovered in one frozen vegetarian burger.

That’s right — when eating a burger, you may be consuming human or rat DNA.

Hollis JohnsonWhile Clear Labs tested 47 fast-food burgers, they aren’t releasing the brands, so it’s impossible to know if products like this Five Guys burger were tested or not.

Though this might sound unappetizing, you do not have to worry as much as it may seem.

Dr. Michael Doyle, a regents professor of food microbiology at the University of Georgia, says the results aren’t as terrible as they first sound.

First, molecular testing can’t differentiate between live and dead pathogens. Cooking burgers kills most pathogens, and once the cells are dead, they can’t make you sick.

Secondly, human and rat DNA are actually a pretty common finds in foods.

“When there is a food handler involved you’re likely to find some form of human DNA,” Doyle said in a statement on the findings. “The FDA has set allowable limits for rat pellets in some food ingredients such as wheat because it’s impossible to remove all traces of rat DNA. It sounds gross, but you have to have to put that in perspective.”

Flickr/copa41Veggie burgers were revealed to be the most problematic category in the report

The bigger issue, according to Doyle, is substitution — a belief backed by Clear Labs data.

More than 6% of samples’ analysis revealed substitutions, with products such beef, chicken, turkey, and pork in burgers that were not supposed to contain these ingredients.

The problem was even more pronounced in veggie burgers, with more than 15% of vegetarian products missing at least one ingredient. For example, one “black bean burger” tested didn’t contain any black beans.

More concerning, substitutions go hand-in-hand with inaccurate nutritional information. Almost half of all samples contained more calories than reported on labels or in menus.

So even while — somewhat surprisingly — the fast-food industry earned top marks when it came to hygiene, 38 of the 47 fast-food burgers analysed had more calories than reported on fast-food menus. Twelve of these had caloric values that were more than 100 calories greater than stated on the menu.

Clear Labs has refrained from naming the fast-food chains or burger brands tested, with a spokesperson telling Business Insider that the company’s goal is to work with the food industry instead of calling out specific retailers or brands.

“Surviving in today’s burger market requires building trust with consumers, who are increasingly questioning the food industry’s processing and manufacturing practices, and differentiating on quality,” Clear Labs writes in the report.

While it is natural to freak out about the possibility of rat DNA in your burger, trace elements of rodents in your food are just a gross fact of life.

What might be worth worrying about, though, is that burger makers could be tweaking recipes in ways that are not represented in the provide nutritional information. That, not the rat DNA, might be the most unnerving aspect of the modern burger industry.